1. Field of the Invention
The present invention relates to a light reflector which is deteriorated little by UV rays and which reflects light from a light source to realize high brightness.
2. Description of the Background
Backlight-type liquid-crystal displays with a built-in light source therein have been much popularized. Of such backlight-type displays, a typical structure of sidelight-type ones comprises a light waveguide with a dot print 12 on a transparent acrylic plate 13, a light reflector 11 provided on one face of the light waveguide, a diffuser 14, and a cold-cathode lamp 15 disposed adjacently on the side of the light waveguide, as in FIG. 1. The light having entered the structure from the side of the light waveguide brightens in the dot print area, and while protected from reflection and leakage by the light reflector 11, it forms uniform surface light though the diffuser 14.
In the backlight unit of the type, the light reflector acts to efficiently utilize the light from the built-in light source for image display and functions to realize the intended image display. In general, glaring mirror reflection is disliked, and it is necessary to realize relatively uniform brightness in the plane direction in a mode of scattering reflection that gives a natural feel to viewers. In particular, the reflector used in sidelight-type liquid-crystal displays is required to reflect the light having passed through the back of the light waveguide, uniformly in the plane direction with no uneven brightness.
Heretofore, white polyester films as in JP-A 4-239540 have been much used for the application as herein.
However, some part near to the light source may be heated up to 80° C. or higher by the heat generated by the light from the light source, and, in addition, the reflector may be yellowed by the light, essentially by UV rays of the light from the light source, and it often causes color change and brightness reduction with time.
In consideration of the related art as above, an object of the present invention is to provide a reflector that is free from the trouble of yellowing as in white polyester films heretofore used in reflectors and is stable against color change for a long period of time.